This was basically my experience on both sides of the process (with a major exception when I interviewed for my current job). I learned from both. On the interviewer side, I sat down and wrote out a framework for how to do a good interview since nobody ever gave me one and I was initially flying blind. (What am I looking for in the person who will do the role? How should I break up the time to check and validate those things?) On the interviewee side, I basically just decided any hiring manager that tries to make you feel bad/stupid almost certainly isn't worth working for. I complete those interviews and try to use them as a learning experience, and I try to exhibit grace in the face of rudeness, then I just move on with my life. It's not always pleasant and required some self-control, but I figure it's a good skill to have on its own.